JP2555097B2 - How to paint and dry automobile bodies - Google Patents

Description

The present invention relates to a method for coating and drying an automobile body.

(Prior art and its problems) When painting an automobile body, it has a preparation process for removing dust adhering to the body, a process for applying paint to the body, and a drying process for drying the applied paint. .

Then, the body normally undergoes the above-mentioned preparation process, painting process, and drying process while being conveyed by a carrier, but the posture of the body is maintained while maintaining a predetermined posture in each process.

After the drying process, the body on the carrier is subjected to manual correction of coating (touch paint), and is removed from the carrier for the purpose of shifting to the next assembly line. Then, the body is held on the carrier by a posture that is convenient for correction of the coating or unloading from the carrier,
Had been transported through the painting line.

(Problems to be Solved by the Invention) By the way, as one criterion for evaluating the quality of a coated surface, there is smoothness (flatness).
The degree of unevenness on the painted surface is small, resulting in a good painted surface.
It is already known that in order to improve the smoothness of the coated surface, the thickness of the coating film, that is, the thickness of the applied coating material may be increased. On the other hand, there is "drip" of the paint that hinders the quality of the painted surface. This sagging is caused by the downward flow of the applied coating due to the gravity, and the larger the thickness of the coating applied at one time, the more easily the “sag” occurs. Since the cause of this "sag" is, after all, the effect of gravity, it tends to occur on the vertically extending surface of the body, that is, the so-called vertical surface.

Therefore, the horizontally extending surface of the body, that is, the so-called lateral surface, in which the "drip" of the paint is not a serious problem, can make the thickness of the applied coating larger than that of the vertical surface. Even if the thickness of the coating film on the horizontal surface is the same as the thickness of the coating film on the vertical surface, the unevenness is reduced by the slight flow of the paint that does not cause sagging on the horizontal surface, resulting in smoothness on the vertical surface. The smoothness is better than the degree.

In view of the above, conventionally, in order to obtain a painted surface with as large a smoothness as possible while preventing "sagging" of the paint, painting has been performed using a paint with as low fluidity as possible. The so-called "drip limit" in which "drip" of the paint occurs on the vertical surface is, for example, in the case of the thermosetting paint, the maximum thickness of the coating film is about 40 µm. More specifically, the "drip" of the thermosetting coating is likely to occur at the beginning of the setting process and the baking process, especially at the beginning of the baking process, and is applied in the coating process so that "drip" does not occur at this time. The thickness of the paint is determined, and the maximum value of the determined thickness, that is, the sag limit value is about 40 μm. Therefore, in order to obtain a coated surface having an absolutely higher smoothness, it is necessary to repeat a series of steps from the coating step to the baking step a plurality of times in the conventional coating method, such as coating twice. there were.

However, if the "drip" phenomenon of the paint is caused by the action of gravity on the paint, the direction of action of gravity on the paint may be positively changed. That is, if the automobile body is rotated around the horizontal axis, it becomes possible to change the direction of action of gravity on the paint applied to the body.
It will be dried without causing "sag".

Thereby, the film thickness of the coating material applied per time can be made much thicker than in the past, and a very good coated surface can be obtained in which the smoothness far exceeds the level which has hitherto been the limit.

However, it has been found that when such a rotation is added to the drying step, a new problem arises in that the melt sheet laid on the floor surface of the passenger compartment peels off. To explain this problem in detail, the melt seat is laid on the floor surface of the passenger compartment in order to prevent noise and vibration between the passenger compartments.
Before the above-mentioned paint drying step, a method is used in which a sheet-shaped melt sheet is laid on the floor surface of the vehicle compartment and fused by heat in the paint drying step. Of course, when this heat fusion is used, it is necessary that the melt sheet and the floor surface are in close contact with each other. However, it is customary to provide a tunnel for passing the drive shaft or the exhaust pipe on the floor of the passenger compartment, and the side wall of this tunnel is almost upright from the floor. The corner part sandwiched between the floor surface and the floor is actually a place where the melt sheet is difficult to adhere to. For this reason, when drying with the vehicle body held in a normal position (with the roof facing up),
Although the problem of peeling of the melt sheet does not occur, when the automobile body is rotated, the heat fusion of the melt sheet becomes incomplete at the corner portion, and the portion melts and separates during the rotation of the automobile body, that is, in the drying process. Fear arises. Needless to say, even if a part of the melt sheet is detached, it causes dust and adversely affects the paint surface which is being dried.

Therefore, an object of the present invention is to provide a method for coating and drying an automobile body, which prevents the peeling of the melt sheet, which tends to occur when the automobile body is rotated in the drying process.

(Means and Actions for Solving Problems) In order to achieve the above-mentioned technical problems, the present invention applies a paint having a sag limit or more to an automobile body and then dries the automobile body while rotating it about a horizontal axis. In the process, after the temperature of the automobile body reaches or exceeds the melting point of the melt sheet laid on the floor surface of the passenger compartment of the automobile body, the rotation of the automobile body is stopped and the roof side of the automobile body is turned up. It is designed to be held in a regular posture.

That is, as will be described later in detail, the peak of the "dripping" of the paint occurs in the initial stage of drying, and therefore the vehicle body may be rotated only during this initial stage of drying. Then, regarding when to stop the rotation of the automobile body, paying attention to the fact that the thermal conductivity of the melt sheet is smaller than that of the automobile body (iron), and when the temperature of the automobile body becomes the melting point of the melt sheet. In addition, the melt sheet can be prevented from peeling off by stopping the automobile body in a normal posture. That is, after the automobile body reaches the melting point of the melt sheet due to the difference in thermal conductivity,
Since the melt sheet reaches its melting point, this time lag causes the melt sheet to begin to melt after the automobile body is in the normal posture.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

Here, in the example, in order to improve the smoothness of the coated surface obtained with the same coating film thickness, in the spraying of the coating material in the coating process, the coating film thickness should be equal to or more than the sagging limit. In the drying process, the body is rotated around the horizontal axis. The rotation of the body around the horizontal axis is stopped on condition that the temperature of the body reaches the melting point of the melt sheet laid on the floor of the passenger compartment. It is designed to be held in a regular position with the side up.

Thereby, the film thickness of the coating material applied per time can be made much thicker than in the past, and a very good coated surface can be obtained in which the smoothness far exceeds the level which has hitherto been the limit.

Also, even when the thickness of the coating film is the same as the conventional one,
By utilizing the fluidity of the coating material, it is possible to obtain an excellent coated surface having smaller irregularities, that is, greater smoothness.

Furthermore, if it is desired to obtain a coated surface having the same smoothness, for example, a smoothness equivalent to that obtained by a conventional coating method, it is possible to reduce the thickness of the coating material to be coated as compared with the conventional one. The amount of paint used can be reduced by the amount that can be thinned. Needless to say, a paint that causes "drip" even in a thin paint film can be obtained by reducing a component that impairs fluidity from a conventional paint by a predetermined ratio.

In addition, since the melt sheet has a lower thermal conductivity than the body, the melting point of the melt sheet is reached after the body reaches the melting point of the melt sheet. It is possible to prevent the generation of dust accompanying this.

Overview of Overall FIG. 1 shows the overall steps for coating an automobile body W as an object to be coated, and each step is indicated by P1 to P7.

First, a body sheet W on which a melt sheet has been laid on the floor of the passenger compartment, and then, undercoating has been completed by electrodeposition coating as is known.
Is sent to the preparation process P1 while being held by the dolly D.
The carriage D includes a drive unit for rotating the body W by utilizing the restoring force (spring force) of the spring, as described later.

In the preparation step P1, dust other than the body W is removed by, for example, air blow or vacuum suction. Then the process
In P2, after the paint (thermosetting paint in the embodiment) is sprayed on the body W, the paint is dried in the setting process P3 and the baking process P4. And
In the embodiment, in the steps P3 and P4, the restoring force of the spring is used to rotate the body W as described below.

After P4, in the transfer process P5, from the dolly D to the body W
Is unloaded, and only the body W is transferred to the next assembly process. On the other hand, in the unwinding process P6, the dolly D with the body W unloaded is given an external force to the spring as the rotation drive source installed in the dolly D, and the restoring force is stored in the spring. After that, in the body mounting process P7, the dolly D with the spring having a restoring force applied thereto.
On the other hand, a body W to be newly painted is mounted. After this, the above-described preparation step P1 is performed again. In this way, the carriage D is circulated and used so as to start from the preparation process P1 and return to the preparation process P1 again.

Relationship between Paint Thickness, Dripping Limit, Smoothness, and Horizontal Rotation FIG. 2 shows the effect of coating film thickness on the sagging limit, focusing on thermosetting paint. FIG. 2 shows three cases of coating film thickness of 40 μm, 53 μm, and 65 μm. For both of these thicknesses, both at the beginning of the setting process and the beginning of the baking process,
It is understood that a "drip" peak occurs. In addition, the sag limit usually means a value when a sag of 1 to 2 mm is generated in one minute (a paint surface is defective if sag of 2 mm / min or more is visually observed). The maximum coating thickness obtained in the range is about 40 μm for the conventional paint.

On the other hand, FIG. 3 shows the influence on the smoothness when the body W is rotated in the horizontal direction and when it is not. A in FIG. 3 shows a state in which the body W is not rotated (conventional coating method). FIG. 3B shows a case where the body W is rotated 90 ° and then reversed (forward / reverse rotation between FIGS. 4 (a) and 4 (c) described later). FIG. 3C shows the case where the body W is rotated 135 ° and then reversed (forward / reverse rotation between FIGS. 4A and 4D described later). FIG. 3D shows the case where the body W is rotated 180 ° and then reversed (forward / reverse rotation between FIGS. 4A and 4E described later). FIG. 3E shows a case where the body W is continuously rotated in the same direction (taken in the order of FIGS. 4 (a), (b), (c) ... (i) described later, Return to (a) again).

As is apparent from FIG. 3, if the thickness of the coating film is the same, it is better to rotate the body W (see FIG. 3, B, C, D,
E), the smoothness is larger than that when not rotated (FIG. 3A). Further, it is understood that it is preferable to rotate 360 ° in the same direction even in the same rotation in order to improve smoothness. Of course, when the body W does not rotate,
Since there is a limit to the thickness of the coating film, there is a limit to increasing the smoothness.

By the way, the thickness of the coating film is 65 μm and the body W is 360
When rotated by °, the obtained smoothness is the image clarity.
It is “87” in IG (lower limit of 1.0 in PGD value). When the thickness of the coating film is 40 μm, when the body W is not rotated, the IG is “58” (lower limit of 0.7 in PGD value), whereas the body W is rotated 360 °. If IG is "68"
(Lower limit of 0.8 in PGD value). As is known,
The IG (image gloss) in the image clarity is a ratio of the image clarity to the mirror surface (black glass) as 100, and the PGD of the painted surface decreases as the identification degree of the reflected image decreases from 1.0. This is the value at which the smoothness decreases.

The test conditions for the data shown in FIGS. 2 and 3 are as follows, and the test conditions show the conditions for topcoating with P2.

Paint: Melamine alkyd (black) Viscosity: Ford cup # 4 22 seconds / 20 ° C b. Coating machine: Minibell (16,000 rpm) Shaping air… 2,0kg / m ₂ c. Leaf yield: 2 times 1st time… 100cc / min 2nd time… 150 to 200cc / min d. Setting time: 10 minutes × normal temperature e. Baking conditions: 140 ℃ × 25 minutes f. Substrate smoothness: 0.6 (PGD value) (Intermediate coating, on PE tape) g. Rotation or reversal operating range: Setting (10 minutes) to baking (10 minutes) h. Workpiece: Paint on the side of a 30 cm square cylinder, rotate around the center Supported as possible i. Rotation speed of coated object: 3 rpm, 6 rpm, 30 rpm, 60 rpm, but there was virtually no difference due to the difference in rotation speed Note that the paint uses the main resin and the curing agent If it is a two-component curing type, sagging occurs only in the setting process P3, and if the paint is a liquid paint, sagging occurs only in the baking process P4. W Rotation of, may be performed only in the setting step P3 only or baking step P4 that the sagging occurs. Further, in the case of powder coating, no setting process is necessary since it does not contain a solvent.

Spraying and drying of paint First, spraying of paint at P2 is performed so that the thickness of the coating film is equal to or greater than the sag limit. That is, in the conventional thermosetting paint that has been generally used, the maximum thickness of the paint that does not cause "sag", that is, the sag limit value is about 40 μm, but in the process P2, the sag limit of 40 μm is far exceeded. The paint is sprayed to give a thick coating. Specifically, a melamine alkyd adjusted to have a viscosity of 20 seconds with a Ford cup # 4 is sprayed so as to form a coating film of 65 μm.

After this P2, it will be immediately transferred to the setting process of P3. In this setting process P3, FIG.
As shown in (i), the body W is rotated in the horizontal direction. That is, the rotation axis l where the body W extends in the horizontal direction
, And in the embodiment, the rotation axis l
Extend in the front-rear direction of the body W. Although the temperature atmosphere in the setting step P3 is room temperature in the embodiment, it may be set to an appropriate temperature in a range lower than the temperature atmosphere in the subsequent baking step P4 such as 40 ° to 60 ° C. Of course, this setting process P3 is for volatilizing the low-boiling point component in the paint in advance, which prevents the generation of hinholes on the painted surface due to the rapid volatilization of the low-boiling component in the next baking process P4. To be done.

In the baking process P4, the paint is baked in a temperature atmosphere of 140 ° C., for example. This P4, as shown in FIG. 5, to a temperature of the body W is 120 ° C., the horizontal axis body W is as shown in FIG. 4 as with setting step of _{P 3 (a) ~ (i} ) It is rotated around. here,
120 ° C is the melting point of the melt sheet laid on the floor of the passenger compartment, and the melt sheet has the following composition.

(Composition of melt sheet) Straight asphalt 30wt% Modified asphalt 33wt% Asbelt (or cellulose fiber) 25WT% Calcium carbonate 9wt% Kiln ash 3wt% And after the body temperature exceeds 120 ℃,
It is held in the normal posture shown in FIG.

Due to the horizontal rotation of the body W at P3 and P4 described above, the paint is dried without dripping even if the paint is sprayed to a thickness greater than the sag limit at P2. As a result, it is possible to obtain a high-quality coated surface having extremely high smoothness, which cannot be obtained by the conventional coating method.

Even if the rotation of the body W is stopped after the temperature reaches 120 ° C., the amount of “sag” after 120 ° is shown by the integrated value in the shaded area in FIG. 5, and this value is extremely small. Also, since the sagging speed is within 0.1 mm / min, the influence on the painted surface is in a negligible range. The thermal conductivity of the melt sheet is lower than that of the body W. Therefore, after the body W reaches 120 ° C., the melt sheet reaches its melting point of 120 ° C., so that the body W is held in a normal posture. In this state, the melt sheet is heat-sealed. Therefore, there is no fear of inducing peeling of the melt sheet.

Truck A truck having a function of rotating the body W.

In FIG. 6, the base 21 of the truck D is driven on the road surface (rail 23) using the wheels 22. A pair of front and rear stays 24 are provided so as to extend downward from the base 21, and a pulling wire 25 is fixed to each of the stays 24. This wire 25 is driven by a motor (not shown) provided at a safe place for explosion protection,
The truck D is driven to travel via 25.

On the other hand, on the base 21, a pair of boxes 26, 27 are fixed at the front and rear ends (left and right ends in FIG. 6). The pair of boxes 26 and 27 serve as a support portion for rotatably supporting the body W via a rotating jig 1 to be described later. Therefore, bearings 28 and 29 are provided on the upper surfaces of the boxes 26 and 27, respectively.
Is fixedly placed. And a pair of boxes 26 and 27
The space between and is a supporting space (rotating space) 30 that is slightly larger than the front-rear length for the body W. The rotary drive portion will be described later.

Rotating jig The rotating jig 1 is roughly divided into a front portion 1F, a rear portion 1R, and a reinforcing connecting portion 2 connecting both portions, as shown in FIGS. 6 and 7. As shown in FIG. 8, the front portion 1F has a continuous portion 3 and a pair of left and right mounting portions 4 which are formed by bending one iron plate or the like. It has a cylindrical rotary shaft portion 5 joined to the continuous portion 3 by welding or the like. The rotating shaft portion 5 is rotatably supported by the box 26 via a bearing 28 (see FIG. 9), and the rotation of the rotating shaft portion 5 is transmitted to the mounting portion 4 via the connecting portion 3. In the embodiment, the attachment portion 4 is detachably attached to the front end portions of the pair of left and right front side frames 11 of the body W using, for example, bolts.

Since the rear side portion 1R of the rotating jig 1 is also configured substantially the same as the front side portion 1F, the corresponding components are designated by the same reference numerals and the description thereof will be omitted. However, the mounting portion 4 of the rear side portion 1R is shaped so as to be fitted in the rear end opening of the rear side frame 12 of the body W in the insertion type without rattling. Of course, the rotary shaft portion 5 of the rear portion 1R is rotatably supported by the box 27 via the bearing 29. The front and rear rotary shaft portions 5 are arranged so as to extend on the same straight line in the front-rear direction and in the horizontal direction with the body W interposed therebetween, and the axis of the rotary shaft portion 5 is the rotation center l. It will be.

The reinforcing connecting portion 2 of the rotating jig 1 is joined to each continuous portion 3 of the front portion 1F and the rear portion 1R by welding or the like. In the embodiment, the reinforcing connecting portion 2 is formed by using two left and right hollow square iron materials. The joining position with respect to the reinforcing connecting portion 2 is set as close to the mounting portion 4 as possible. The side frames 11 and 12 are at least partially seated on the reinforcing connecting portion 2 and the body W
The weight of is also supported by the parts other than the mounting part 4. Further, the reinforcing connecting portion 2 is fixed to the front side frame 11 and the rear side frame 12 by a bracket or the like at a position apart from the mounting portion 4 by the bracket 6, so that the body W rotates more reliably without rattling. It is connected to the jig 1.

Balance Weight It is preferable that the rotation center 1 of the body W passes through the center of gravity G (see FIG. 6) of the composite of the body W and the rotating jig 1. That is, by making 1 and G coincide with each other, it is possible to prevent rotation fluctuation. If it is difficult to match 1 and G with each other, a balance weight may be provided on the rotation shaft system of the body W including the rotation jig 1.

An example of such a balance weight B is shown in FIG. Reference numeral 41 in FIG. 8 denotes a first screw rod, which is installed between a pair of left and right mounting portions 4 in the front portion 1F of the rotating jig 1. A first weight 42 is screwed onto the first screw rod 41, and one end of a second screw rod 43 is fixed to the first weight 42. The second screw rod 43 extends in a direction orthogonal to the first screw rod 41, and the second weight 44 is screwed onto the second screw rod 43.

Therefore, by changing the screwing position of the first weight 42 with respect to the first screw rod 41, the body W and the rotary jig 1 are changed.
The final position of the center of gravity G'of the rotary shaft system including the balance weight B and the balance weight B is adjusted in the vehicle width direction. Further, by adjusting the screwing position of the second weight 4 with respect to the second screw rod 43, the vertical position of the center of gravity G'is adjusted.
Furthermore, by adjusting the circumferential position of the first weight 42 with respect to the first screw rod 41, the center of gravity G ′ can be adjusted downward and upward by the second weight 44, as well as in the front-back direction. (The height position of the first weight 42 is adjusted in advance so that the center of gravity G passes near the height of the first weight 42). In this way, the position of the center of gravity G ′ of the rotary shaft system is adjusted so that the center of gravity G ′ coincides with the rotation center l.

Of course, such adjustment of the center of gravity G'is performed at an appropriate time before rotating the body W, and in the embodiment, before the preparatory step P1, more specifically, when the body W is mounted on the carriage D. I am going to do it.

Rotational Drive (Outline) Drive units K1 and K2, which will be described later, are arranged in the boxes 26 and 27, respectively. This drive unit K
Includes at least a spring as a drive source, and an output shaft 31 to which the power from the drive source is transmitted extends to the outside of the box 26 or 27. And each output shaft 31
Is transmitted to the front and rear rotary shafts 5 via a transmission mechanism 32 including a sprocket and a chain.

The rotation drive units K1 and K2 will be described.
One drive unit K1 is for start-up, and the other drive unit K2 is for continuous rotation.

Drive Unit K2 (for Continuous Rotation) Drive Source The drive unit K2 has, as shown in FIG. 10 and FIG. 11, a casing 61, one storage drum 62 and four winding drums 63 rotatably supported. . Winding drum
63 is smaller in diameter than the animal power drum 62 and is in the circumferential direction.
They are arranged at 90 ° intervals. Each of the drums 62 and 63 has three drum portions 62a or 63a partitioned by flanges in the respective axial directions. A spring 64 extending in a thin plate shape is wound between each drum portion 62a of the animal power drum 62a and each drum portion 63a of each winding drum 63. That is, one end 6a of the spring 64 is fixed to the drum portion 62a, while the other end 64b is fixed to the drum portion 63a. The total of four springs 64 extending from the four take-up drums 63 are arranged so as to be four-fold wound around the storage drum 63.

The spring 64 is adapted to be in a free state when it is wound around (the drum portion 63a of) the winding drum 63. Therefore, when the spring 64 is wound around the input drum 62, the spring 64 is equivalent to the spring. The state in which the spring force is applied to the spring 64, that is, the state in which the spring 64 generates a restoring force is set. More specifically, when the spring 64 is wound around the livestock drum 62, the restoring force generates a restoring force such that the spring 64 is wound around the winding drum 63, and based on the restoring force. The energy storage drum 62 is rotationally driven (the energy storage drum 62 also serves as a rotary take-out mechanism for taking out the restoring force of the spring 64 as a rotational force). Further, in the embodiment, the spring 64 is of constant load type, that is, it is always made to generate a restoring force of a constant torque. As a result, if the load on the power storage drum 62 is constant, the power storage drum 62, that is, its rotating shaft. 62b is rotated at a constant speed.

Speed-up mechanism L The rotation of the rotary shaft 62b in the above-mentioned animal power drum 62 is the twelfth
It is transmitted to the output shaft 31 via the speed increasing mechanism L shown in FIGS. The speed increasing mechanism L includes a casing 66 that is arranged close to the casing 61 and also constitutes a part of the box 27.
The input shaft 67 and the intermediate shaft 68 are rotatably supported.
The input shaft 67 receives the rotational force from the rotating shaft 62b of the animal power drum 62. Then, the rotation of the input shaft 67 is transmitted to the intermediate shaft 68 via the speed increasing gears 69A and 69B, and the rotation of the intermediate shaft 68 is transmitted to the output shaft 31 via the speed increasing gears 70A and 70B. .

Constant load mechanism M As shown in FIG. 13, a brake drum 56 is integrated with the output shaft 31, and a shoe 58 urged by a spring 57 is in contact with the brake drum 56. A constant load mechanism M including these elements 56, 57, 58 applies a constant load corresponding to the biasing force of the spring 57, and the rotation of the output shaft 31 based on the restoring force of the spring 64 as the rotary drive source. However, the rotation speed is set to be even more constant.

Ratchet mechanism N Further, the output shaft 31 has a casing 66 (box 2
6) The ratchet gear 71 is fixed to the outside, and the ratchet pawl 72 is engaged with and disengaged from the ratchet gear 71 (see also FIG. 14). The ratchet pawl 72 is swingably supported by the casing 66 around the pin 73, and is operated to engage and disengage from the ratchet gear 71 by operating a lever 74 connected thereto. Such a ratchet mechanism N has a ratchet gear 71 (output shaft
The rotation direction of 31) in the clockwise direction of FIG. 14 is the direction rotated by the restoring force by the spring 64 as a rotation drive source, and the ratchet gear 71 and the ratchet pawl 72 are provided.
In the engaged state, the restoring force of the spring 64 prevents the output shaft 31 from rotating. In other words, by manually operating the lever 74, for example, the rotation of the spring 64 serving as the rotation drive source and the rotation inhibition (stopping the extraction of the restoring force) can be performed using the restoring force.

Incidentally, reference numeral 32a in FIG. 13 is fixed to the output shaft 31 and is connected to the transmission mechanism 3
Reference numeral 33 is a sprocket that constitutes a part of 2, and 33 is an engaging portion for rewinding a spring 64 described later (rewinding external force input section).
Is.

Ratchet Operating Mechanism O To automatically switch the operation of the ratchet mechanism N when the carriage D reaches a predetermined position, for example, the following operation can be performed. This point will be described with reference to FIG. To do. In FIG. 15, the ratchet mechanism N is arranged in the box 27.

First, the guide bar 75 is fixedly arranged along the traveling path of the carriage D. The surface of the guide bar 75 facing the carriage D is composed of a low portion 75a, a high portion 75b, and a tapered surface 75c that smoothly connects the both portions.

On the other hand, a bell crank 77 is swingably supported by a bracket 76 fixed to the box 27, and the base end of the input rod 8 is connected to one end of the bell crank 77 and
An output rod 79 connected to the lever 74 is connected to the other end of the bell crank 77. The input rod 78 is slidably held by the bracket 76 in the direction orthogonal to the carrying direction of the carriage D, and a roller 80 as a follower is rotatably attached to the tip end portion thereof. Then, the spring 81 causes the roller 80 to move the guide bar.
It is urged to always contact 75.

With the above configuration, the position of the lever 74 is
Depending on the height position of the guide bar 75 with which 80 abuts, the ratchet mechanism N prevents rotation of the output shaft 31 when it abuts a high portion 75b in the embodiment, and conversely the roller 80 moves to a lower portion 75a. When the contact is made, the output shaft 31 is allowed to rotate.

Drive unit K1 (for start-up) The drive unit K1 portion provided in the box 26 will be described with reference to FIGS. 16 and 17. The same components as those of the drive unit K2 are designated by the same reference numerals, and the description thereof will be omitted.

First, the structure of the spring 64 as a rotary drive source, the storage drum 62, and the winding drum 63 is the same as that of the drive unit K2 for continuous rotation described above.
The drive unit K2 differs from the drive unit K2 in that only one spring 64 and one spring 64 are provided. The rotation force is applied to the rotating jig 1 based on the restoring force of the spring 64 via the reduction gear and the clutch.

First, in the box 26, the clutch plate 85a and the clutch drum 85b of the friction clutch 85 are rotatably supported, and the gear 86 fixed to the outer periphery of the clutch plate 85 is
It is meshed with a gear 87 fixed to a rotating shaft 62b of the storage drum 62. The gears 86 and 87 form a reduction mechanism, and therefore the gear 86 has a larger diameter than 87.

The clutch output shaft arranged in the clutch drum 85b is the output shaft 31. Therefore, when the clutch 85 is connected, the rotation of the power drum 62 (rotating shaft 62b) based on the restoring force of the spring 64 is reduced and the output shaft 3
Transmitted to 1. As a result, a large torque required at the time of starting is secured.

The clutch 85 is interposed to quickly disconnect the start-up spring 64 from the rotating jig 1 after the body W starts rotating. That is, the spring is for starting
The restoring force of 64 is decelerated and transmitted to the output shaft 31, so that the restoring force of the body W is lost by, for example, about one rotation of the body W (when wound on the winding drum 63). End). On the other hand, even if the spring 64 for continuous rotation has the same length as the spring 64 for starting, since the body W is rotated via the speed increasing mechanism L, the spring for starting is
Body W with more revolutions (eg 10 revolutions) compared to 64
Will be able to rotate. Then, after starting, the clutch 85 is disengaged so that the starting spring 64 does not hinder the rotation of the body W.

In order to automatically engage and disengage the clutch 85, in the embodiment, the winding amount of the spring 64 (the radial size of the drum 62 including the spring 64) with respect to the storage drum 62 is detected, and this winding amount is The clutch 85 is disengaged when it becomes almost zero.

A mechanism Q for detecting the winding amount of the spring 64 around the storage drum 62 is as shown in FIG. That is, a lever 89 is swingably supported around the pin 88 with respect to the box 26, and a spherical body 90 as a follower is rotatably held at the tip of the lever 89. Then, the lever 89 is urged by the spring 91 so as to always contact the outer peripheral surface (the wound spring 64) of the animal power drum 62. This lever 89 has a cable 92
Are connected. That is, the cable 92 is an outer tube whose both ends are fixed to the box 26.
The inner wire 92b has an inner wire 92b disposed therein, and one end of the inner wire 92b is connected to the lever 89. Then, as shown in FIG. 16, the other end of the inner wire 92b is connected to the clutch release lever 85c of the clutch 85.
It is connected to.

As a result, when the winding amount of the spring 64 around the animal power drum 64 becomes small and the restoring force of the spring 64 becomes almost zero, the inner wire 92 is displaced by the displacement of the lever 89.
The release lever 85c is displaced via b, and the clutch 85 is disengaged.

Fixed posture stopper mechanism R This mechanism keeps the rotation of the body W in a normal posture when the temperature of the body W9 reaches 120 ° C.

An electric temperature sensor may be used to detect the temperature of the body W, but a shape memory alloy that transforms at 120 ° C. is used from the viewpoint of explosion protection.

18 to 20, the fixed posture stopper mechanism R is shown.
Is a stopper 105 fixed on the box 26 or 27.
It has. The stopper 105 has a casing 105a, and a stopper rod 105b is vertically movably fitted in the casing 105a. The stopper rod 105b is
The return spring 105c is attached in the contracting direction. On the other hand, the base end of the stopper rod 105b and the casing
A shape memory alloy 105d is arranged between the lower surface of 105a and the shape memory alloy 105d, and the shape memory alloy 105d takes a contracted shape at room temperature and transforms into an elongated shape at 120 ° C. Then, at the tip of the stopper rod 105b, a sphere 105e as a follower is formed.
Are rotatably held.

Such a stopper rod 105e. Its tip (sphere
105e) faces the side surface of the rotating shaft portion 5 of the rotating jig 1, and correspondingly, a locking recess 106 is formed on the outer peripheral surface of the rotating shaft portion 5. When the spherical body 105e is fitted into the locking recess 106, the body W takes a normal posture with its roof side facing upward, and this regular posture is maintained by the shape memory alloy 105d.
Is made by continuing to take an elongated shape (see Figure 20 (b)). Of course, the shape memory alloy 105d is a Fi-Ni alloy,
An-Cd alloy, Cu-Zn-X alloy (X = Si, Su, Al), Ni-
Various materials such as Al alloy can be used.

Modified Example of Fixed Position Stopper Mechanism R In FIGS. 21A and 21B, the fixed position stopper mechanism R is a stop lever provided on the box 26 or 27.
It has 110. The stop lever 110 is swingably supported around a pin 111, and one end 110a of the stop lever 110 is the rotating shaft portion 5 described above.
A shape memory alloy 112 and a return spring 113 are installed between the box 26 or 27 at the other end 110b of the stop lever 110 facing the side surface of the. The shape memory alloy 112 is
It is said that it takes a contracted shape at room temperature and transforms into an elongated shape at 120 ° C. When the shape memory alloy 112 is transformed into an elongated shape, the locking lever 110 swings counterclockwise in the figure, and one end 110a of the locking lever 110 is formed on the outer peripheral surface of the rotary shaft portion 5. It is adapted to be fitted into the locking recess 114 and to stop the rotation of the body W (see FIG. 23 (b)). At this time, the body W takes a regular posture. As another modification, as shown in FIGS. 22 (a) and 22 (b), the shape memory alloy 12 may be replaced with a bimetal 114 made of, for example, amber and bronze. Here, Fig. 22 (a) shows the state at room temperature, and Fig. 22 (b)
Shows the state at 120 ° C.

Transfer device In step 5, unloading the body W from the dolly D, or in the step
It is a device for mounting the body W on the carriage D at P7. An example of this is shown in FIGS. 23 to 25.
The explanation will focus on the one for P5. This transfer device is
As shown in the figure, the carriage movement locus R1 on the coating line and the movement locus R2 of the carriage or hanger in the assembly process are installed close to each other at the transfer station S1. The transfer device installed in the transfer station S1 is substantially constituted by a lifter 51 as shown in FIG. 23 and FIG. The lifter 51 includes a pair of left and right guide posts 52 and each guide post.
A base 53 is attached to the base 52 so as to be vertically driven, and a support leg 54 is driven so as to be capable of expanding and contracting from each base 53. Each of the support legs 54 has a pair of front and rear support portions 54a which are spaced apart in the moving direction of the carriage.

In the above structure, the trolley D supporting the body W from the coating line is stopped at the transfer station S1. When the dolly D is stopped, the support legs 54 are extended from the lowermost base 53, and then the base 53 is moved upward. As a result, as shown in FIGS. 23 and 24, the body W on the carriage D is lifted from the carriage D while the side sills or floor frame portions of the body W are supported by the support portions 54a of the support legs 54. Elevated to a higher position. After that, the dolly D for the assembly line is located at the transfer station S1. After that, the base 53 is lowered and the body W is transferred to the carriage for the assembly line. Then, the supporting leg 54 is contracted in preparation for the next transfer (see the alternate long and short dash line in FIG. 23). In this way, the body W is transferred from the truck for the painting line to the truck for the assembly line.

Of course, the unloading of the body W from the dolly D is
Is performed in a state of a predetermined rotation posture, and the holding of this predetermined rotation posture is ensured by the stopper mechanism R described above.

On the other hand, the mounting of the body W on the carriage D in P7 may be performed in the reverse order of the above procedure, and the body W mounted on the carriage D at this time is, of course, the one before painting.

It should be noted that when the body W is transferred, it is preferable that the dolly D be firmly fixed in a predetermined position in an immovable state by a positioning device or the like that clamps the dolly D from the front and rear and the left and right directions. Further, the transfer device has a hanger that is intermittently fed at a high place, and after the lifter 51 transfers the hanger to the hanger, the hanger moves the body W above the carriage for the assembly line. At the position, the body may be transferred from the hanger to the carriage D for the assembly line by using the lifter again.

Rewinding mechanism T This is for accumulating (stores restoring force) in the rotation spring 64 (64-1, 64-2). In the present embodiment, the rewinding mechanism T is provided in the non-explosion-proof zone in the transport path of the carriage D immediately before the body W before painting is mounted on the carriage D.

As shown in FIG. 26, the rewinding mechanism T includes a pair of left and right guide posts 121, and sliders 122 fitted to the respective guide posts 121 so as to be vertically movable. This slider 1
Each of the motors 22 is moved up and down by a motor 123 via a wire 124. A holding bar 125 is provided between the pair of left and right sliders 122.
The casing 1 is installed in the middle of the holding bar 125.
26 is fixed. In this casing 126, the 27th
As shown in the figure, an air motor 27 and a speed reducer 128 are provided, and thus the rotation of the motor 127 is reduced by the speed reducer 128. The output shaft 128a of the speed reducer 128 is the casing 1
26 is extended to the outside, and an engaging box 129 is provided at its tip.
Has been fixed.

With the above configuration, when the carriage D approaches,
When the casing 126 is lowered and the truck D further approaches, the rewinding engaging portion 33 provided on the truck D is engaged with the engaging box 129. After this, the motor
127 is driven to rotationally drive the engaging portion 33, and the rotation spring 64 stores the force.

After this energy saving, the truck D is temporarily retracted with respect to the rewinding mechanism T, and then the casing 126 is moved upward.
After that, the carriage D is moved to the next step P7 through the space between the left and right guide posts 121.

As the rewinding mechanism T, a dedicated actuator may be separately provided, or the displacement of the carriage D with respect to the rail 23 may be used. In this case, for example, the rack bar is fixedly arranged along the traveling path of the carriage D for a predetermined length, while the carriage D is rotatably supported by a gear meshing with the rack bar, and the gear is rotated as the gear rotates. Spring
64 may be rewound (for example, a gear and an energy storage drum 62 using a wire and a drum wound around the wire).
Connection with). Of course, the rack bar is provided by a length corresponding to the number of rotations of the gear required for the spring force. In such a case, if rack bars are provided at a plurality of locations along the movement trajectory of the carriage D, for example, immediately before each of the steps P1, P3, and P4, for example, the rack bars are shown in FIGS.
The length of the spring 64 used in the illustrated embodiment may be short.

(Effects of the Invention) As is apparent from the above description, according to the present invention, it is possible to obtain a coated surface having extremely good smoothness without causing the problem of peeling of the melt sheet.

[Brief description of drawings]

FIG. 1 is an overall process diagram showing an embodiment of the present invention. 2 and 3 are graphs showing the relationship between the thickness and sag of the paint, the smoothness of the coated surface, and the rotation. FIG. 4 is a diagram showing a state in which the posture of the automobile body, which is an object to be coated, changes as the body rotates. FIG. 5 shows the body W, the temperature change, and the body W in the embodiment.
Is a graph showing the relationship with the rotation stop timing of. FIG. 6 is a side view showing an example of a body transporting trolley and a rotating jig for rotating the body. FIG. 7 is a plan view of FIG. 6 showing a carriage and a rotating jig. FIG. 8 is a perspective view showing a front portion of the rotating jig. FIG. 9 is a left side view of FIG. 7. FIG. 10 is a front view of an essential part showing an example of installation of a continuous rotation spring. FIG. 11 is a partial cross-sectional plan view of FIG. 10 seen from above. FIG. 12 is a simplified front view of the speed increasing gear mechanism as viewed from the axial direction. FIG. 13 is a partial cross-sectional plan view taken along the line XIII-XIII in FIG. FIG. 14 is a side view of an essential part showing a ratchet mechanism that performs rotation and rotation locking by a rotation spring. FIG. 15 is a plan view of essential parts showing an example for automatically operating the ratchet mechanism of FIG. FIG. 16 is a plan sectional view showing a device portion of the starting spring. FIG. 17 is a sectional view taken along the line YY of FIG. FIG. 18 is a perspective view showing an example of a stopper mechanism for holding the body W in a normal posture. FIG. 19 is a front view of the stopper mechanism used in FIG. FIG. 20 is a cross-sectional view of the stopper included in the stopper mechanism. The figure (a) shows the state at room temperature, and the figure (b) shows the state at 120 ° C. or higher. FIG. 21 shows a modified example of the stopper mechanism for holding the body W in the normal posture. FIG. 21 (a) shows the state at room temperature, and FIG. 21 (b) shows the state at 120 ° C. or higher. . FIG. 22 shows another modified example of the stopper mechanism for holding the body W in a normal posture. The figure (a) shows the state at room temperature, and the figure (b) shows the state at 120 ° C. or higher. Is. 23 to 25 show an example of a transfer device for the article to be coated on the carriage D. FIG. 23 is a front view, FIG. 24 is a side view, and FIG.
FIG. 25 is a simplified plan view showing the movement trajectory of the carriage. 26 and 27 show an animal power device for applying a restoring force to the rotating spring, and FIG. 26 is a perspective view,
FIG. 27 is a side view. P1 to P7: Process (P3, P4: Drying process) R: Fixed posture stopper mechanism W: Vehicle body l: Horizontal rotation axis D: Transport carriage K1, K2: Drive unit 105: Stopper 105d: Shape memory alloy

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-158725 (JP, A) JP-A-56-141881 (JP, A) JP-A-56-115665 (JP, A)

Claims (1)

(57) [Claims] 1. In a process of applying a paint having a sag limit or more to an automobile body and then drying the automobile body while rotating the automobile body around a horizontal axis, the temperature of the automobile body is laid on a floor of a passenger compartment of the automobile body. After the temperature exceeds the melting point of the melt sheet, the rotation of the car body is stopped and the roof body of the car body is kept in a normal position so that the car body is kept in a normal position. .